Apparently, this company has the sole right to issue ISBNs; no other company in the USA is legally allowed to do so. This is highly unusual, since it is a for-profit corporation, not a government agency. So I must be missing something—why is this possible?

Imagine if the government required car license plates, but instead of issuing them itself or through its affiliates, there was a parasitic middleman that the government required you to buy from. I know ICANN is somewhat similar, but ICANN is effectively a child of a U.S. defense agency, so it makes sense—and you can buy domains from multiple companies.

Why isn’t ISBN funded and run by a government agency, like the U.S. Trademark Office?